Study on the Synergistic Extraction of Lithium from Spent Lithium Cobalt Oxide Batteries by Molten Salt Electrolysis and Two-Step Precipitation Method

Abstract

With the continuous development of society, the number of spent lithium-ion batteries has also increased, and the recovery of valuable metals such as Ni, Co, and Li has become the main research direction of many scholars. In this paper, the extraction process of lithium that enters the molten salt after LiCoO2 electrolysis is studied. Oxalic acid and phosphate are added to molten salt containing lithium ions to realize the two-part precipitation method to extract lithium. The influence of pH value, temperature, reaction time, and oxalic acid (or phosphate) addition on the process of oxalic acid calcium removal and phosphate lithium precipitation is analyzed. The results show that the calcium removal rate of oxalic acid has reached 99.72% (Initial conditions: PH = 7.0, T = 70 °C, t = 1.5 h, n(H2C2O4):n(Ca2+) = 1.2:1). The precipitation of Li3PO4 obtained in the phosphate extraction experiment of lithium is as high as 88.44% (Initial conditions: PH = 8.0, T = 70 °C, t = 1.5 h, n(actual dosage of Na3PO4):n(theoretical dosage of Na3PO4) = 1.2:1). The obtained lithium phosphate crystals show regular spherical particles, which can be seen by SEM.

A Review of Recovering Lithium and Cobalt from Spent LiCoO2 Lithium‐Ion Batteries Cathode

“…The regenerated LiCoO 2 exhibited 93 % of capacity retention after 100 cycles. An experiment that added phosphate and oxalic acid to the molten salt for obtaining lithium phosphate precipitate was conducted by Li [149] . Influences of temperature, pH value, reaction time, even oxalic acid or phosphate addition were analyzed and the precipitation of Li 3 PO 4 reached 88.44 %.…”

Reviewing Advanced Treatment of Hydrocarbon-Contaminated Oilfield-Produced Water with Recovery of Lithium

“…Although this method requires more steps in processing to convert Li phosphate into Li carbonate or hydroxide, it might cut down on processing time and costs [72]. Sodium phosphate salts, including di-sodium phosphate, tri-sodium phosphate, sodium pyrophosphate, and sodium tri-polyphosphate, have been utilized in various research studies [73][74][75][76]. The study conducted by Alsabbagh et al [76] showed suitable salts for lithium-precipitating reagents, with tri-sodium phosphate (TSP) recovering 40% of lithium in the Dead Sea evaporated end brine.…”

Combinatorial mixtures of organic solutes for improved liquid/liquid extraction of ions

“…[33][34][35] This synergistic extraction process has garnered significant research attention for metal ion separation or purification, 36,37 and is generally explained in terms of the formation of an extraction complex that includes participation of more than one molecular species. 38,39 Chang et al in 2017 used oleic acid as the liquid organic phase to study the extraction of copper ions from water (Fig. 1(a)).…”

“…33–35 This synergistic extraction process has garnered significant research attention for metal ion separation or purification, 36,37 and is generally explained in terms of the formation of an extraction complex that includes participation of more than one molecular species. 38,39…”